The first portion of work related to analysis of concentrations of progesterone and estriol in weekly saliva samples collected as part of this trial. Results of this analysis were presented at the annual meetings of the Society for Maternal-Fetal Medicine and the Society for Pediatric and Perinatal Epidemiologic Research. A manuscript describing the results was published in FY 2009. It was found that compared with placebo, 17-alphahydroxyprogesterone did not alter the normal increase in salivary progesterone as pregnancy progressed. However, 17P did slow the rise in salivary estriol with increasing gestation. The salivary progesterone:estriol ratio increased with advancing gestation in women receiving placebo, but remained flat among women receiving 17P. The p-values for interaction were highly significant for salivary progesterone and the estriol: progesterone ratio. In the second portion of this project, DESPR investigators have participated in the design and conduct of a recently completed project to follow the children from the 17P trial at age 2-5 to assess the presence of morbidity at that age. No statistically or clinically significant adverse impact of in-utero exposure to 17P were observed in cognitive development, physical growth, blood pressure, gender specific play, birth defects or general health were found. In a related project, DESPR investigators participated in the design, conduct and reporting of a randomized, double blind placebo controlled clinical trial, conducted by the MFMU Network, to determine whether supplementation with 2000 mg of Omega-3 fatty acids (DHA and EPA) would prevent recurrent preterm birth. Treatment was not associated with a difference in preterm birth recurrence (38% among treated versus 42% among control women). However, women who consumed fish had a significantly lower incidence of preterm birth regardless of whether they were assigned to supplementation or placebo. Results were presented at the 2008 meeting of the Society for Maternal Fetal Medicine, and a manuscript is currently in preparation. DESPR Investigators have conducted a secondary analysis of the omega-3 trial, addressing the association between fish consumption and preterm birth. A U-shaped dose-response was observed, with women who consumed low-to-moderate amounts of fish having the lowest occurrence of preterm birth-- the nadir was reached at approximately 2 servings per week. Women who consumed no fish, and those who consumed larger amounts than 2-3 servings/week, experienced higher occurrence of preterm birth. Interestingly, the association between fish consumption and preterm birth was essentially identical among women who received omega-3 supplements or placebo. This suggests that if the association between moderate fish consumption and reduced preterm birth is causal, it is probably not due to Omega-3 fatty acids. Other nutrients, such as vitamin D, may be responsible. Environmental contaminants in fish might account for the association between higher consumption and the increase in preterm birth. As with any observational study, residual confounding cannot be ruled out. Results were presented at the annual meeting of the Society for Pediatric and Perinatal Epidemiologic Research.